The present invention relates to sterile surgical fasteners, used to occlude bodily tissue structures, and the methods and instruments for applying such fasteners. More particularly, this invention relates to sterile clips, and instruments and methods for placement of such clips, that are used to ligate tubular structures within the body, such as blood vessels, to impede the flow of bodily fluid therethrough.
In order to prevent excessive fluid loss or bleeding during a surgical procedure, a surgeon will typically have to ligate or close various fluid ducts and/or blood vessels before severing those vessels. There are many types of mechanisms or devices for shutting off the vessels such as ligating clips, hemostatic clips and the like. In some instances the surgeon will tie a ligature or suture about a vessel to close or shut the vessel. Ligating clips are well known in the art. Many of the clips are metal and comprise a pair of legs which are connected at one end. The vessel to be ligated is placed between the legs and the legs forced together about the vessel to close the vessel. Clips have also been developed from plastic materials. However, since plastics do not have the same strength and malleability characteristics as metals, the plastic clips typically include some type of locking mechanism so that when the legs are urged together about the vessel they are locked in a closed position.
Ligating clips should ensure closure of the vessel. That is, they should completely shut off blood flow or other fluid flow and not allow leakage. Also, the clips should remain closed, should not open or break and should not slip or slide out of position or off the vessel. While it doesn't take much force to collapse and close a vessel, the clips that are now typically used require substantial force to close or change configuration so that once closed, the clip will remain in its closed position.
In minimally invasive surgery, in particular, endoscopic surgery, it has become desirable to provide smaller instruments capable of reaching surgical sites through smaller access ports. Smaller incisions cause less damage in accessing the surgical site and the access wounds from such incisions heal faster. In presently known clip appliers, the size of the instrument is dictated, in general, by the size of the clip as it is passed through the clip applying instrument to its business end, and the size of the jaws used to crush the clips closed. Clips are passed through the clip applying instrument in an open position so as to allow the clip to capture a tissue structure to be ligated before the jaws crush the clip closed over the structure.
It is therefore an object of the invention to provide a clip which is contained in a space-efficient, closed position until it reaches the structure to be ligated, thus enabling the use of smaller access ports.
In endoscopic surgery, the business end of the instrument is placed within the body through an appropriate cannula, body canal or small incision. The manipulation of that business end by the surgeon is accomplished outside the body. As a result, it becomes more difficult to control the business end of the instrument since it is further removed from the actual operation of the instrument. Any slight movement in the manipulation of the instrument outside the body is magnified at the business end of the instrument. Therefore, there is a greater chance in an endoscopic procedure that a slight movement of a clip applier as a clip is being closed will cause clip misplacement. This is particularly true considering that conventionally available clips require high force to effectively form over a tissue structure.
It is therefore another object of the present invention to substantially reduce the forces required to endoscopically apply a clip to ligate a structure such as a blood vessel. The less force required to place a clip, the greater the chance of accurate clip placement and therefore of positive vessel closure throughout the surgical procedure. Further, the force used to crush the clip also crushes the tissue and making the clip hard to remove, if so desired. Also, the less force required to place a clip on a vessel the less likely the vessel will be cut or lacerated.
It is a further object of the present invention to provide a clip and clip applier which allow a user to close off a vessel and determine whether the positioning is appropriate before applying the ligating clip.
Clips now typically used are applied with a clip applier which crushes the clip to a preset dimension. Although a range of clip sizes exist to provide for ligation of a variety of tissue structure sizes, frequently, the present dimension is too large for a smaller structure or too small for a larger structure. If the structure is too small or too large, or conversely stated, if the clip gap of the closed gap is too large or too small, the clip has a greater chance of being misplaced, of providing inadequate ligation force or of slipping off the vessel.
Furthermore, the presently used clips typically comprise two legs attached at one end. Therefore, the closure force varies along the length of the clip, the greater force being closer to where the legs are attached. Thus with such a clip configuration, the chances are greater that the clip will slip from the closure site, particularly if the tissue is slightly misplaced towards the clip opening.
It is therefore an object of the invention to provide a clip and applier which reduce the chances of the clip slipping from the ligated vessel site or of providing insufficient ligation. It is an object of the invention to provide a clip and a method of applying the clip to a wider range of vessel sizes. It is also an object of the invention to provide a clip which provides substantially uniform ligating force along the length of the clip.
Though the novel clip, instrument and methods of the present invention are most appropriate for use in endoscopic procedures and will be so described in the following, it should be pointed out that the clip and/or the instrument could also be used quite capably in traditional open type surgical procedures.